1. Field of the Invention
The present invention relates generally to the field of non-destructive testing, and in particular to a new and useful ultrasonic probe having a pipe-encircling, low profile configuration for the onsite inspection of pipes.
2. Description of the Related Art
The CANadian Deuterium Uranium or CANDU reactor contains complex arrays of pipes. One of these arrays is shown in part in FIG. 11. The pipes of these arrays must be tested onsite (in-situ) at various times during the life of the reactor. Because of the complex nature and close spacing of the CANDU pipe arrays, access to the pipes for testing is difficult.
Corrosion, erosion, and cracking are problems in industrial piping that can be detected by ultrasound (UT). For inspections, sound is generated by a transducer and sent into a target component. The reflections, or echoes, from the generated sound are then received after exiting the component and used to detect defects. As transmission of ultrasound through air into a typical test component is less than ideal, the inspecting transducer(s) should be coupled to the target component by a material that allows a significant portion of the sound to be transmitted into the component. Typically field inspections are done in contact by attaching a plastic shoe or wedge in between the transducer and the target component. The plastic is generally constructed to match the shape of the target component, and a coupling medium, such as gel or water, of thickness less than one wavelength is used at the plastic-to-metal interface to minimize air gaps. This method tends to work well if the target component is smooth and of known geometry. If the surface of the component is non-uniform or the component has geometry changes such as elbows or welds, then the plastic shoe can lift off the surface of the component and cause loss of signal.
Immersion ultrasonic testing is typically performed in a laboratory or production environment where an immersion tank can be used and has many advantages over contact ultrasonic testing but is not well adapted to onsite testing.
A need exists for a low profile, on-site, UT pipe tester that is capable of accessing and testing the pipes in a complex array.